Fluid expandable tire building drum with shoe means attached thereto to form a tire building surface

ABSTRACT

A fluid expandable drum for building portions of tires in a tire building machine includes an annular supporting drum and an expandable annular tube element having an inner peripheral surface supported on the annular drum. The tube element includes an outer peripheral surface upon which support means is secured for movement therewith. A plurality of shoe members are connected to the support means for movement therewith with the shoe members defining an annular building surface thereon which is movable in a radial direction toward and away from the annular support drum upon contraction and expansion, respectively, of the tube element. The tube element is expanded to expand the diameter of the building surface to enable a tire portion to be built thereon and retracted to decrease the diameter of the building surface to enable a build tire portion to be removed therefrom.

PRIOR ART STATEMENT

The following reference is considered to be relevent to the presentinvention:

U.S. Pat. No. 3,475,254 filed by Henley

The Henley U.S. Pat. No. 3,475,254 discloses a tire building machinehaving a plurality of segments 221 which are biased by springs 224 intoengagement with the tube elements.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fluid expandable drum for building atread and a radial tread ply band in a tire building machine and moreparticularly to a fluid expandable drum which includes support meanspositively affixed thereto for supporting a plurality of shoe elementswhich define an annular building surface which is movable in a radialdirection with the support means upon expansion and contraction of thetube element. The shoe means is operable to decrease the diameter of thebuilding surface upon contraction of the tube element without the needfor auxiliary springs.

2. Background of the Invention

Fluid expandable drums for building tires are well known in the art. Anexample of known tire building machinery is dislocsed in the Henley U.S.Pat. No. 3,475,254; the Appleby, et al. U.S. Pat. No. 3,784,437; and theIredell U.S. Pat. No. 2,614,951. Also, machines such as the NRM ModelR1016 Second Stage Radial Tire Building Machine have also been used inthe art for the construction of tires.

Some known tire building machines generally utilize a tire building drumwherein a plurality of shoe means are utilized to form the tire buildingsurface. The shoe means are biased outwardly in a radial direction uponexpansion of a fluid expandable element. Spring means are provided toretract the shoes and decrease the diameter of the tire building surfaceupon contraction of the tube element. Such a construction is shown inHenley U.S. Pat. No. 3,474,254 wherein the springs 160 are utilized tourge the gap shields 161 inwardly, and in the Iredell U.S. Pat. No.2,614,951 wherein springs 22 urge the segments 6 in an inwardlydirection. The use of spring means to return the shoes and the buildingsurface to their contracted position increases the cost, complexity andreliability of the known tire building mechanisms. Moreover, the use ofsuch springs considerably increases the difficulties in replacing anexpandable tube element in the tire building machine due to the factthat all of the spring means must be released before the tube elementcan be replaced.

SUMMARY OF THE INVENTION

The present invention provides a new and improved fluid expandable drumfor building a tread and a radial tread ply band in a tire buildingmachine including an annular supporting drum and an expandable annulartube element having an inner peripheral surface supported on the annularsupport drum and an outer peripheral surface. Support means is securedto the outer peripheral surface of the tube element for movementtherewith. The shoe means define an annular building surface which ismovable in a radial direction toward and away from the annular supportdrum upon contraction and expansion, respectively, of the tube element.The tube element is expanded to expand the diameter of the buildingsurface to enable a tread and a radial tread ply band to be builtthereon and retracted to decrease the diameter of the building surfaceto enable a built tread and a radial tread ply band to be removedtherefrom.

The present invention further provides a new and improved annular fluidexpandable tube element for use with an annular drum for buildingportions of tires in a tire building machine including a lower wallportion having an inner surface and an outer surface adapted to besupported on the drum and an upper wall portion having an inner surfaceand an outer surface. The upper wall portion is movable radiallyoutwardly from the lower wall portion upon expansion of the tube elementand is movable radially toward the lower wall portion upon contractionof the tube element. Support means are secured to the outer surface ofthe upper wall portion and a plurality of shoe means are supported bythe support means for movement therewith. The plurality of shoe meansdefine an annular building surface which is movable in a radialdirection away from the drum upon expansion of the tube element toexpand the diameter of the building surface to enable a portion of atire to be built thereon and movable in a radial direction toward thedrum upon contraction of the tube element to decrease the diameter ofthe building surface to enable a built tire portion to be removedtherefrom.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the annular fluid expandable tubeelement of the present invention.

FIG. 2 is a cross-sectional view of the annular fluid expandable tubeelement of the present invention illustrating the annular support drumupon which the tube is supported and the shoe means for defining thebuilding surface.

FIG. 3 is a side view taken approximately along the lines 3--3 of FIG. 2more fully illustrating the annular drum and tube element and includinga fragmentary showing of the retainer ring.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the figures, an expandable tube element 10 for use in atire building machine is illustrated. The tube element 10 is shown inFIGS. 2 and 3 supported on the outer annular peripheral surface 8 of atire building drum 12 which is normally supported in a tire buildingmachine not illustrated. The tire building drum 12 includes a flangeportion 14 which is secured to a shaft 16 for rotation therewith by abolt 18 and tapered bushing 20. Suitable well-known means are providedin the tire building machine to effect rotation of shaft 16 and, hence,drum 12 to enable a tire portion, in the preferred embodiment a treadand a radial tread ply band, to be built thereon.

The tube element 10 includes an upper wall portion 22 and a lower wallportion 24. The upper wall portion 22 includes an outer peripheralsurface 26 and an inner interior surface 28 and the lower wall portion24 includes an outer peripheral surface 30 and an inner surface 32. Theouter peripheral surface 30 of the lower wall portion 24 is adapted tobe supported on the annular peripheral surface 8 of the drum 12 forrotation therewith. The tube element 10 has a contracted condition as isillustrated in full lines in FIG. 2 and an expanded condition,illustrated in phantom lines in FIG. 2 in which a fluid, such as air, isintroduced through a valve 15 into the cavity 34 to effect radialmovement of the upper wall portion 22 away from the drum 12 and lowerwall portion 24.

Secured to the upper wall portion 22 are a plurality of shoe members 36which in part define an annular tire building surface 38 upon whichportions of tires are constructed. Expansion of the tube element 10effects an increase in diameter of the annular tire building surface 38and contraction of the tube element 10 effects a decrease in diameter ofthe tire building surface 38.

The outer peripheral surface 26 of the upper wall portion 22 includes aplurality of support blocks 40 which may be bonded thereto or formedintegrally therewith in an annular array. The support blocks 40 eachinclude a cylindrical opening 42 disposed therein which enables a shoemember 36 to be attached thereto. It should be appreciated that each ofthe support blocks 40 has one shoe member 36 affixed thereto formovement therewith.

Each of the shoe members 36 include a planar portion 44 and a pair ofside portions 46 which extend substantially perpendicular from theplanar portion 44. A flange 48 extends from each of the side portions 46in an outwardly direction. Each of the side portions 46 includes anopening 50 therein which is adapted to receive a rod member 52 therein.The rod member 52 extends through the openings 50 in the side portions46 of the shoe 36 and passes through the opening 42 in the support block40 to interconnect the shoe 36 and the support block 40. Suitable means,such as the E-clips 54, are provided to secure the rod 52, relative tothe shoe 36 and support block 40, once rod 52 is passed through theopenings 50 and 42. The rod 52 connects the shoe member 36 to thesupport block 40 disposed on the tube element 10 so that the shoe member36 moves radially inwardly and outwardly upon contraction and expansion,respectively, of the tube element 10 without the need for auxiliaryreturn springs.

Each of the shoe members 36 includes punched tabs 56 in the planarsurface 44 which are disposed apart a distance equal to the width of thesupport block 40. The tabs 56 engage the upper corners of the supportblock 40 to center and support the shoe member 36 relative to thesupport block 40. As is more fully illustrated in FIG. 3, each of theshoe members 36 includes radially projecting side portions 58 at theedges thereof.

Secured to the planar surface 44 of each of the plurality of shoemembers 36 is a gap plate 60. Each of the gap plates 60 is secured via aweld 62 to the surface 44 of a shoe member 36. It should be apparentfrom FIG. 3 that the gap plates 60 are not centrally located on thesurface 44 of the shoe members 36. Rather, the gap plates are offsetrelative to the shoe members 36 so that the gap plates 60 extend acrossthe gaps formed by the radially projecting side portions 58 of adjacentshoe members 36. Upon expansion of the tube element 10, the shoe members36 move in a radially outwardly direction causing the planar surface 44of each of the shoe members 36 to move apart thereby accentuating thespace or gap formed between the side portions 58 of adjacent shoemembers 36. The plurality of planar surfaces 44 cooperate to define theannular building surface 38 upon which the tire portion is built and thegap plates 60 cooperate with the planar surfaces 44 to define asubstantially continuous annular building surface 38 around the exteriorof the drum 12. When the tube 10 is expanded, the shoe members 36 moveradially outwardly causing the gap plates 60 to slide in a tangentialdirection as the building surface 38 expands. The gap plates 60 are ofsufficient length so that when the tube element 10 reaches its fullyexpanded condition, the gap plates still cover the gaps formed by theadjacent side portions 58 of the shoe members 36. The gap plates 60 formthe building surface 38 upon which a portion of a tire is built. Itshould be apparent that the gap plates 60 and the planar surfaces 44provide a substantially continuous annular building surface 38 about theperiphery of the drum 12 when the tube element 10 is in its expanded andcontracted condition.

In the present embodiment, the expandable drum 12, as illustrated in thefigures, is utilized for building a tread and a radial tread ply band.The tread and radial tread ply band are utilized in producing radialtires and are subsequently combined with a tread portion and cured toform the tire. The plys of the tread and radial tread ply band areplaced on the building surface 38 when the tube element 10 is in itsexpanded condition. This controls the size of the tread and radial treadply band. After the tread and radial tread ply band have been completed,the tube element 10 is contracted thereby contracting the shoe members36 and the building surface 38. Contraction of the building surface 38causes the gap plates 60 to slide in a tangential direction over theplanar surfaces 44 as the diameter of the building surface 38 decreases.The tangential movement of the gap plates 60 upon contraction of tubeelement 10 loosens the built tread and radial tread ply band from thebuilding surface 38 so that it can be removed from a subsequentoperation.

The diameter of the tread and radial tread ply band formed on thebuilding surface 38 is extremely critical. Accordingly, a pair ofannular retainer rings 64 are secured to the sides of the annular drum12 via bolt members 66. The retainer rings 64 include an inwardlyprojecting flange member 68 which includes an interior surface 70. Thesurface 70 of each of the retainer rings 64 is adapted to engage withthe flanges 48 disposed on either side of the shoe member 36 to limitthe radial movement of the shoe member 36 upon expansion of the tubeelement 10 and fix the diameter of the building surface 38 when the tubeelement 10 is expanded. It should be apparent that various retainerrings 64 could be utilized to vary the size of the building surface tobuild various sized tread and radial tread ply bands. The retainer rings64 are easily replaceable by removing the bolts 66.

The tube element 10, as is more fully illustrated in FIG. 1, includes arubber inner tube 72 which is preferably formed from neoprene. Bonded tothe outside of the rubber inner tube is a radial ply 74. Bonded to theradial ply 74 is a rubber cover 76 which is also preferably formed fromneoprene. (Rubber and neoprene will be used interchangeably in thespecification, and it is Applicant's intention that both of these termsbe considered generic for rubber or rubber-like resilient coatings.)Disposed between the cover 76 and the radial ply 74 adjacent the annulararray of support blocks 40, is a radial ply band 78. The radial ply band78 has an annular shape and extends around the circumference of the tubeelement 10 beneath the support blocks 40. The radial ply band 78 differsfrom the radial ply 74 in that the radial ply band 78 is an annular bandwhich only extends in the upper wall portion 22 adjacent the supportblocks 40 while the radial ply 74 has a conventional construction andextends throughout the entire wall portion of the tube element. Theradial ply band 78 provides resiliency and adds strength to the upperwall portion 22 of the tube element 10. The provision of the radial plyband 78 enables the tube element 10 to contract to its original positionand, thus, move the shoe members 36 and the building surface 38 in aradially inwardly direction without the need for auxiliary springs dueto the strength and resiliency added by the band 78.

The construction of the tube element 10 enables the tube to withstand a30% circumferential strain which occurs upon expansion of the tubeelement 10 to various diameters as the retainer rings 64 are varied toenable the apparatus to be utilized to construct various sized tires. Itshould be appreciated that upon expansion of the tube element 10, theside portions thereof must be resilient to provide for a uniformexpansion to various diameters of the tube while the tube must haveenough strength to support the support blocks 40 and the shoe members 36for movement therewith and while a tread and a radial tread ply isconstructed on the building surface 38. Thus, the combination of theradial ply 74 for adding overall strength to the tube and the radial plyband 78 for adding stength and resiliency in the upper portion 22 of thetube element 10 is desirable. Such a construction provides the requiredstrength in the building surface 38 while not making the tube so stiffthat it would not withstand a 30% circumferential strain upon expansion.Additionally, a minimum durometer rubber is preferably used to reducelocal stresses in the corners or sides of the tube element 10.

A filler block 80 is secured to the inner surface 32 of the lowerportion 24 of the tube element 10. The filler block 80 is preferablymade of rubber or neoprene and acts to stiffen the lower wall portion 24of the tube element 10 and decrease the volume of fluid needed to bedirected to the chamber 34 to effect expansion of the tube element 10.The filler block 80 acts like a rubber band in tension to hold thecenter of the lower wall portion 24 against the surface 8 of the drum12. This prevents the tube 10 from rolling on the surface 8 uponexpansion due to a slight nonsymetrical construction of the tube 10caused by manufacturing inaccuracies. The filler block 80 also preventssagging of the upper wall portion 26 when it is disposed below the lowerwall portion 24 by adding rigidity to the lower wall portion 24. Whenthe tube element 10 is placed on the annular drum 12, the lower half ofthe tube element, not illustrated, will have the shoe members 36essentially hanging from the bottom portion of the annular tube member10 and the lower wall portion 24 will be disposed vertically above theupper wall portion 26. If the filler block 80 were not provided, theweight of the shoe members 36 would cause the upper wall portion 26 ofthe lower half of the tube 10 to sag due to the weight of the shoemembers 36 acting thereon which would also pull downwardly on the lowerwall portion 24. This downward pull on the lower wall portion 24 wouldcause the lower wall portion 24 to sag if not for the force of thefiller block 80 acting thereon in a direction tending to bias the tubeto the surface 8 of drum 12. Thus, the filler block 80 acts to addrigidity to the lower wall portion 24 and prevent sagging of the upperwall portion 26 of the lower half of the tube 10. Additionally, thefiller block 80 acts as a stop to limit the inward radial movement ofthe upper wall portion 26 to maintain substantial concentricity of theupper wall 26 relative to the surface 8 of drum 10.

From the foregoing, it should be apparent that a new and improved fluidexpandable drum for building tread and radial tread ply bands in a tirebuilding machine has been provided. The fluid expandable drum includesan outer surface 8 for supporting an expandable tube element 10 havingan inner peripheral surface 30 supported on the annular outer surface 8of the drum 12. A support block 40 is secured to the outer peripheralsurface of the upper wall portion 26 of the tube element 10 and aplurality of shoe members 36 are connected to the support member 40 bythe rods 52 for movement with the support blocks 40. The shoe members 36define an annular building surface 38 which is movable in a radialdirection relative to the drum 12 upon expansion and contraction of thetube element. The tube element includes a radial ply extending aroundthe cross-sectional circumference of the tube element and a radial plyband extending around the outer peripheral surface adjacent the supportblocks to increase the strength and resiliency of the outer peripheralsurface to enable the shoe means to decrease the diameter of thebuilding surface upon contraction of the tube element without the needfor auxiliary springs.

We claim:
 1. A fluid expandable drum for building a tread and a radialtread ply band in a tire building machine comprising an annular supportdrum having an annular outer surface thereon, an expandable annular tubeelement having an inner peripheral surface supported on said annularouter surface of said support drum and an outer annular peripheralsurface, support means rigidly secured to said outer annular peripheralsurface of the tube element for movement therewith, a plurality of shoemeans rigidly connected to said support means for movement therewith,said plurality of shoe means cooperating to define an annular buildingsurface thereon which is movable in a radial direction toward and awayfrom said annular support drum upon contraction and expansion,respectively, of said tube element, said tube element being expanded toexpand the diameter of said building surface to enable a tread and aradial tread ply band to be built thereon and contracted to decrease thediameter of said building surface to enable a built tread and radialtread ply band to be removed therefrom.
 2. A fluid expandable drum forbuilding a tread and a radial tread ply band in a tire building machinecomprising an annular support drum having an annular outer surfacethereon, an expandable annular tube element having an inner peripheralsurface supported on said annular outer surface of said support drum andan outer annular peripheral surface, support means secured to said outerannular peripheral surface of the tube element for movement therewith, aplurality of shoe means connected to said support means for movementtherewith, said plurality of shoe means cooperating to define an annularbuilding surface thereon which is movable in a radial direction towardand away from said annular support drum upon contraction and expansion,respectively, of said tube element, said tube element being expanded toexpand the diameter of said building surface to enable a tread and aradial tread ply band to be built thereon and contracted to decrease thediameter of said building surface to enable a built tread and radialtread ply band to be removed therefrom, said support means including aplurality of support blocks bonded to said outer peripheral surface ofsaid tube element, each of said support blocks including an openingtherein for receiving a portion of said shoe means therein to securelyaffix the shoe means to said support blocks for movement therewith uponexpansion and contraction of said tube element.
 3. A fluid expandabledrum for building a tread and a radial tread ply band as defined inclaim 1 wherein said plurality of shoe means include a plurality of shoemembers each of which includes a planar member having a substantiallyplanar outer surface and a pair of side walls extending away from saidplanar surface and disposed substantially perpendicular to said planarsurface, each of said planar outer surfaces of said plurality of shoemembers cooperating to form said building surface for building a treadand a radial tread ply band, said planar member and said perpendicularside walls of each of said shoe members being disposed in an overlyingrelationship with one of said plurality of support blocks.
 4. A fluidexpandable drum for building a tread and a radial tread ply band asdefined in claim 3 wherein said side walls of said shoe members eachincluding an opening, a rod member disposed substantially parallel tosaid planar surface and substantially perpendicular to said side wallsand extending through said openings in said side wall and said openingin said support block to interconnect said shoe member to said supportblock for movement therewith.
 5. A fluid expandable drum for building atread and a radial tread ply band as defined in claim 3 furtherincluding a plurality of gap plates one of which is associated with eachof said shoe members, each of said gap plates being connected to saidplanar surface of its associated shoe member and extending in adirection substantially tangential to and forming a part of saidbuilding surface, said gap plates being operable to move in a tangentialdirection relative to said building surface upon contraction of saidtube element to thereby loosen a tread and a radial tread ply band whichhas been built on said building surface.
 6. A fluid expandable drum forbuilding a tread and a radial tread ply band as defined in claim 4wherein said planar surface of said shoe member has a plurality of tabsdisposed thereon for engaging with said support blocks when said shoe isattached thereto for locating said shoe means relative to said supportblock.
 7. A fluid expandable drum for building a tread and a radialtread ply band as defined in claim 3 further including a pair of annularretainer rings one of which is connected to each end of said annulardrum, each of said retainer rings having an annular flange disposedsubstantially parallel to the planar surface of said shoe member, eachof said side walls of said shoe member further including flange meansextending substantially perpendicular to said side walls in a directionaway from said planar outer surface, said flange means on said shoemembers engaging with said annular flange on said retainer ring to limitthe radial movement of said building surface upon expansion of said tubeelement.
 8. A fluid expandable drum for building portions of tires in atire building machine comprising an annular support drum having anannular outer surface thereon, a fluid expandable tube element having alower wall portion having an inner surface and an outer surface adaptedto be supported on said annular outer surface of said drum and an upperwall portion having an inner surface and an outer surface, said upperwall portion being movable radially outwardly from said lower wallportion upon expansion of the tube element and being movable radiallytoward said lower wall portion upon contraction of said tube element,support means secured to said outer surface of said upper wall portionfor movement therewith and a plurality of shoe means secured to saidsupport means for movement therewith, said plurality of shoe meanscooperating to define an annular building surface thereon which ismovable in a radial direction away from the drum upon expansion of thetube element to expand the diameter of the building surface to enable aportion of a tire to be built thereon and movable in a radial directiontoward the drum upon contraction of the tube element to decrease thediameter of the building surface to enable a built tire portion to beremoved therefrom.
 9. A fluid expandable drum for building portions oftires as defined in claim 8 wherein said support means includes aplurality of support blocks bonded to said outer peripheral surface ofsaid tube element for movement therewith, each of said plurality of shoemeans being supported by one of said support blocks.
 10. A fluidexpandable annular drum for building portions of tires in a tirebuilding machine comprising an annular support drum having an annularouter surface thereon, a fluid expandable tube element having a lowerwall portion having an inner surface and an outer surface adapted to besupported on said annular outer surface of the drum, an upper wallportion having an inner surface and an outer surface, said upper wallportion being movable radially outwardly from said lower wall portionupon expansion of the tube element and being movable radially towardsaid lower wall portion upon contraction of said tube element, supportmeans secured to said outer surface of said upper wall portion, aplurality of shoe means supported by said support means for movementtherewith, said plurality of shoe means cooperating to define an annularbuilding surface thereon which is movable in a radial direction awayfrom the drum upon expansion of the tube element to expand the diameterof the building surface to enable a portion of a tire to be builtthereon and movable in a radial direction toward the drum uponcontraction of the tube element to decrease the diameter of the buildingsurface to enable a built tire portion to be removed therefrom, saidsupport means including a plurality of support blocks bonded to saidouter peripheral surface of said tube element for movement therewith,each of said plurality of shoe means being supported by one of saidsupport blocks, said support blocks including an opening therein forreceiving a portion of said shoe means therein to securely affix theshoe means to said support blocks for movement therewith upon expansionand contraction of said tube element.
 11. A fluid expandable tubeelement for use with an annular drum for building portions of tires asdefined in claim 10 wherein said plurality of shoe means include aplurality of shoe members each of which includes a planar member havinga substantially planar outer surface and a pair of side walls extendingaway from said planar surface and disposed substantially perpendicularto said planar surface, each of said planar outer surfaces of saidplurality of shoe members cooperating to form said building surface forbuilding portions of tires, said planar member and said perpendicularside walls of each of said shoe members being disposed in an overlyingrelationship with one of said plurality of support blocks.
 12. A fluidexpandable drum for building portions of tires as defined in claim 11wherein said side walls of said shoe members each including an opening,a rod member disposed substantially parallel to said planar surface andsubstantially perpendicular to said side walls and extending throughsaid openings in said side wall and said opening in said support blockto interconnect said shoe member to said support block for movementtherewith.
 13. A fluid expandable drum for building portions of tires asdefined in claim 11 further including a pair of annular retainer ringsone of which is connected to each end of said annular drum, each of saidretainer rings having an annular flange disposed substantially parallelto the planar surface of said shoe member, each of said side walls ofsaid shoe member further including flange means extending substantiallyperpendicular to said side walls in a direction away from said planarouter surface, said flange means on said shoe members engaging with saidannular flange on said retainer ring to limit the radial movement ofsaid building surface upon expansion of said tube element.
 14. Anannular fluid expandable tube element for use with an annular drum forbuilding portions of tires in a tire building machine comprising a lowerwall portion having an inner surface and an outer surface adapted to besupported on the drum, an upper wall portion having an inner surface andan outer surface, said upper wall portion being movable radiallyoutwardly from said lower wall portion upon expansion of the tubeelement and being movable radially toward said lower wall portion uponcontraction of said tube element, support means rigidly secured to saidouter surface of said upper wall portion, a plurality of shoe meansrigidly secured to said support means for movement therewith, saidplurality of shoe means cooperating to define an annular buildingsurface thereon which is movable in a radial direction away from thedrum upon expansion of the tube element to expand the diameter of thebuilding surface to enable a portion of the tire to be built thereon andmovable in a radial direction toward the drum upon contraction of thetube element to decrease the diameter of the building surface to enablea built tire portion to be removed therefrom, and a plurality of gapplates one of which is associated with each of said shoe members, eachof said gap plates being connected to said building surface of itsassociated shoe member and extending in a direction substantiallytangential to and forming a part of said building surface, said gapplates being operable to move in a tangential direction relative to saidbuilding surface upon contraction of said tube element to thereby loosena built tire portion which has been built on said building surface.